Question 1

A polypeptide chain may have abrupt changes in direction and restriction in geometry because of the presence of

Accepted Answer

A) arginine. 
B) glycine. 
C) proline. 
D) leucine or isoleucine. 
A) arginine. 
B) glycine. 
C) proline. 
D) leucine or isoleucine.

Question 2

Affinity chromatography can be used to save many purification steps compared to other techniques due to its high specificity for the target protein.

Accepted Answer

A) True 
 B)False

Question 3

Hydropathy is an important determination of protein-chain folding because

Accepted Answer

A) it predicts accurately where charged amino acids will appear in a protein. 
B) it describes a specific type of folding. 
C) it distinguishes enzymes from structural proteins. 
D) hydrophobic R groups tend to cluster in the interior of proteins. 
A) it predicts accurately where charged amino acids will appear in a protein. 
B) it describes a specific type of folding. 
C) it distinguishes enzymes from structural proteins. 
D) hydrophobic R groups tend to cluster in the interior of proteins.

Question 4

Amino acids which are not incorporated into polypeptides are sometimes converted into

Accepted Answer

A) neurotransmitters. 
B) methyl donors. 
C) antibiotics. 
D) blood flow controllers. 
E) All of the above. 
A) neurotransmitters. 
B) methyl donors. 
C) antibiotics. 
D) blood flow controllers. 
E) All of the above.

Question 5

The R group of an amino acid determines if it is

Accepted Answer

A) hydrophilic or hydrophobic. 
B) polar or nonpolar. 
C) charged or uncharged. 
D) an acid or a base. 
E) All of the above. 
A) hydrophilic or hydrophobic. 
B) polar or nonpolar. 
C) charged or uncharged. 
D) an acid or a base. 
E) All of the above.

Question 6

The ionic charges associated with a protein molecule are ________.

Accepted Answer

A) mostly contributed by the side chains of constituent amino acids 
B) determined by the contribution from the α-carboxyl group,α-amino group and side chain of every amino acid in the protein 
C) contributed by only the N-terminal and C-terminal residues 
D) independent of the amino acid composition and depend only on pH 
A) mostly contributed by the side chains of constituent amino acids 
B) determined by the contribution from the α-carboxyl group,α-amino group and side chain of every amino acid in the protein 
C) contributed by only the N-terminal and C-terminal residues 
D) independent of the amino acid composition and depend only on pH

Question 7

Match the following to their functions.
-First amino acid in newly synthesized bacterial proteins

Accepted Answer

A) N-formylmethionine 
B) Histamine 
C) S-adenosylmethionine 
D) g-aminobutyrate 
E) selenocysteine
F)epinephrine (adrenaline) 
A) N-formylmethionine 
B) Histamine 
C) S-adenosylmethionine 
D) g-aminobutyrate 
E) selenocysteine
F)epinephrine (adrenaline)

Question 8

The pKa's of isoleucine's α-Carboxyl group and α-Amino group are 2.3 and 9.8,respectively.Calculate the isoelectric point.

Accepted Answer

A) 2.3 
B) 6.0 
C) 9.8 
D) The isoelectric point cannot be calculated without the pKa value for the side chain. 
A) 2.3 
B) 6.0 
C) 9.8 
D) The isoelectric point cannot be calculated without the pKa value for the side chain.

Question 9

Match the following to their functions.
-Neurotransmitter

Accepted Answer

A) N-formylmethionine 
B) Histamine 
C) S-adenosylmethionine 
D) g-aminobutyrate 
E) selenocysteine
F)epinephrine (adrenaline) 
A) N-formylmethionine 
B) Histamine 
C) S-adenosylmethionine 
D) g-aminobutyrate 
E) selenocysteine
F)epinephrine (adrenaline)

Question 10

The pKa of a certain weak acid is 4.0.Calculate the ratio of proton acceptor to proton donor at pH 7.0.

Accepted Answer

A) 1000:1 
B) 20:1 
C) 3:1 
D) 1:1 
E) The ratio cannot be calculated without knowing the structure of the weak acid. 
A) 1000:1 
B) 20:1 
C) 3:1 
D) 1:1 
E) The ratio cannot be calculated without knowing the structure of the weak acid.

Question 11

The hydropathy of amino acids can help determine the folding of protein chains.

Accepted Answer

A) True 
 B)False

Question 12

Tyrosine and tryptophan are less hydrophobic than phenylalanine because

Accepted Answer

A) phenylalanine has an indole group. 
B) phenylalanine has no polar group in the side chain. 
C) phenylalanine is a phenol. 
D) tyrosine and tryptophan have smaller R groups. 
E) All of the above. 
A) phenylalanine has an indole group. 
B) phenylalanine has no polar group in the side chain. 
C) phenylalanine is a phenol. 
D) tyrosine and tryptophan have smaller R groups. 
E) All of the above.

Question 13

The pH inside cells is normally near pH 7.At pH 7 which statement is true about the charges (ionization state)of the α-Carboxyl and α-Amino groups of an amino acid?

Accepted Answer

A) The α-Carboxyl group is 1- and the α-Amino group is 1+. 
B) The α-Carboxyl group is 1+ and the α-Amino group is 1-. 
C) The α-Carboxyl group is 1- and the α-Amino group is uncharged. 
D) Both groups are uncharged (not ionize
D) at pH 7. 
A) The α-Carboxyl group is 1- and the α-Amino group is 1+. 
B) The α-Carboxyl group is 1+ and the α-Amino group is 1-. 
C) The α-Carboxyl group is 1- and the α-Amino group is uncharged. 
D) Both groups are uncharged (not ionize
D) at pH 7.

Question 14

What is the purpose of treating a protein with 2-mercaptoethanol?

Accepted Answer

A) To hydrolyze the protein into its amino acids. 
B) To cleave the disulfide bonds. 
C) To derivatize any free sulfhydryl groups to prevent them from reforming disulfide bonds. 
D) To derivatize the N-terminal amino acid during the Edman degradation. 
A) To hydrolyze the protein into its amino acids. 
B) To cleave the disulfide bonds. 
C) To derivatize any free sulfhydryl groups to prevent them from reforming disulfide bonds. 
D) To derivatize the N-terminal amino acid during the Edman degradation.

Question 15

The liquid emerging from the bottom of a chromatography column is called the ________.

Accepted Answer

A) eluate 
B) supernatant 
C) solute 
D) lysate 
A) eluate 
B) supernatant 
C) solute 
D) lysate

Question 16

Match the following to their functions.
-Methyl donor in metabolism

Accepted Answer

A) N-formylmethionine 
B) Histamine 
C) S-adenosylmethionine 
D) g-aminobutyrate 
E) selenocysteine
F)epinephrine (adrenaline) 
A) N-formylmethionine 
B) Histamine 
C) S-adenosylmethionine 
D) g-aminobutyrate 
E) selenocysteine
F)epinephrine (adrenaline)

Question 17

Which amino acids are linked in phenylalanylglycine?

Accepted Answer

A) Phenyline,alanine and glycine. 
B) Phenol,alanine and glycine. 
C) Phenylalanine and glycine. 
D) Phenol,adenine and glycine. 
A) Phenyline,alanine and glycine. 
B) Phenol,alanine and glycine. 
C) Phenylalanine and glycine. 
D) Phenol,adenine and glycine.

Question 18

Ultraviolet (UV)light can be used to estimate concentrations of proteins in solutions because tryptophan and tyrosine absorb light at a wavelength of 280 nm.

Accepted Answer

A) True 
 B)False

Question 19

Calculate the approximate relative molecular mass,Mr,for a protein with 527 amino acid residues.

Accepted Answer

A) 5.27 × 106 
B) 5.8 × 104 
C) 4.8 
D) 1.7 × 10-5 
E) Cannot determine without knowing the exact sequence of amino acids. 
A) 5.27 × 106 
B) 5.8 × 104 
C) 4.8 
D) 1.7 × 10-5 
E) Cannot determine without knowing the exact sequence of amino acids.

Question 20

The peptide bond is which of the following?

Accepted Answer

A) An amide bond. 
B) An ester bond. 
C) An ether bond. 
D) An amine bond. 
A) An amide bond. 
B) An ester bond. 
C) An ether bond. 
D) An amine bond.

Exam 3: Amino Acids and the Primary Structures of Proteins

A polypeptide chain may have abrupt changes in direction and restriction in geometry because of the presence of

Affinity chromatography can be used to save many purification steps compared to other techniques due to its high specificity for the target protein.

Hydropathy is an important determination of protein-chain folding because

Amino acids which are not incorporated into polypeptides are sometimes converted into

The R group of an amino acid determines if it is

The ionic charges associated with a protein molecule are ________.

Match the following to their functions. -First amino acid in newly synthesized bacterial proteins

The pKa's of isoleucine's α-Carboxyl group and α-Amino group are 2.3 and 9.8,respectively.Calculate the isoelectric point.

Match the following to their functions. -Neurotransmitter

The pKa of a certain weak acid is 4.0.Calculate the ratio of proton acceptor to proton donor at pH 7.0.

The hydropathy of amino acids can help determine the folding of protein chains.

Tyrosine and tryptophan are less hydrophobic than phenylalanine because

The pH inside cells is normally near pH 7.At pH 7 which statement is true about the charges (ionization state)of the α-Carboxyl and α-Amino groups of an amino acid?

What is the purpose of treating a protein with 2-mercaptoethanol?

The liquid emerging from the bottom of a chromatography column is called the ________.

Match the following to their functions. -Methyl donor in metabolism

Which amino acids are linked in phenylalanylglycine?

Ultraviolet (UV)light can be used to estimate concentrations of proteins in solutions because tryptophan and tyrosine absorb light at a wavelength of 280 nm.

Calculate the approximate relative molecular mass,Mr,for a protein with 527 amino acid residues.

The peptide bond is which of the following?

Introduction to Biochemistry

Water

Proteins: Three-Dimensional Structure and Function

Properties of Enzymes

Mechanisms of Enzymes

Coenzymes and Vitamins

Carbohydrates

Lipids and Membranes

Introduction to Metabolism

Glycolysis

Gluconeogenesis, the Pentose Phosphate Pathway, and Glycogen Metabolism

The Citric Acid Cycle

Electron Transport and Atp Synthesis

Photosynthesis

Lipid Metabolism

Amino Acid Metabolism

Nucleotide Metabolism

Nucleic Acids

DNA Replication, repair, and Recombination

Transcription and RNA Processing

Protein Synthesis

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